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      <title>什么是Nginx - 交互式测验</title>
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    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>什么是Nginx - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
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                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
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                    <div id="hint-container" class="hint-container"></div>
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                  <button id="prev-btn" class="nav-btn">上一题</button>
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      <script>
        const quizData = [
  {
    "question": "Nginx能够以较低的资源消耗高效处理数千个并发连接，其核心架构优势是什么？",
    "options": [
      "传统的为每个请求创建新线程的多线程模型。",
      "完全依赖操作系统内核进行请求调度的单进程模型。",
      "采用分布式计算节点来分摊请求处理压力。",
      "基于事件驱动和异步非阻塞的I/O模型。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "Nginx采用事件驱动模型（如epoll）和异步非阻塞I/O。这使其能够在单个工作进程中处理大量并发连接，而无需为每个连接创建昂贵的线程或进程，从而极大地降低了上下文切换和内存消耗的开销，这是其高性能的关键。",
    "source": "文档中「Nginx的架构」部分的「1. 事件驱动模型」和「2. 异步非阻塞I/O」",
    "hint": "文档提到 “Nginx采用了事件驱动和异步非阻塞的架构，使其能够高效地处理大量的并发连接”。"
  },
  {
    "question": "在Nginx的多进程架构中，“主进程 (master process)” 的主要职责是什么？",
    "options": [
      "执行SSL/TLS加密和解密操作。",
      "负责管理工作进程（worker processes）的生命周期，如启动、停止和重启。",
      "直接处理和响应客户端的HTTP请求。",
      "缓存静态文件内容以加速响应。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "Nginx采用多进程架构，其中主进程（master process）不直接处理请求，而是负责管理工作进程。它的职责包括读取和验证配置文件、启动/停止/重启工作进程等。实际的请求处理是由工作进程完成的。",
    "source": "文档中「Nginx的架构」部分的「3. 多进程架构」",
    "hint": "主进程就像一个“经理”，而工作进程是真正的“员工”。想一想经理的核心工作是什么？"
  },
  {
    "question": "在Nginx配置文件中，哪个配置块（block）用于定义一组后端服务器，以便进行负载均衡？",
    "options": [
      "`server` 块",
      "`upstream` 块",
      "`http` 块",
      "`location` 块"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`upstream` 块专门用于定义一个后端服务器池。在这个块内部，你可以列出多个 `server` 指令，指向不同的后端服务器。然后，在 `location` 块中通过 `proxy_pass` 指令引用这个 `upstream` 块的名称，从而实现负载均衡。",
    "source": "文档中「配置文件结构」部分的「6. Upstream块」",
    "hint": "在网络流量中，“上游”通常指代请求最终要流向的服务集群。"
  },
  {
    "question": "假设你需要确保来自同一用户的请求始终被转发到同一台后端服务器（例如，为了维持登录状态），你应该选择哪种Nginx负载均衡算法？",
    "options": [
      "最少连接 (Least Connections)",
      "加权轮询 (Weighted Round Robin)",
      "IP哈希 (IP Hash)",
      "轮询 (Round Robin)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "IP哈希 (IP Hash) 算法通过计算客户端IP地址的哈希值来决定将请求分发到哪个后端服务器。只要客户端的IP地址不变，其请求就会始终被发送到同一台服务器，这对于需要会话保持（session persistence）的应用场景非常有用。",
    "source": "文档中「负载均衡」部分的「负载均衡算法」",
    "hint": "哪种算法利用了客户端的一个独特且相对稳定的信息来做决策，以实现请求的定向分发？"
  },
  {
    "question": "根据文档描述，反向代理中的“SSL卸载 (SSL Offloading)”指的是什么？",
    "options": [
      "反向代理处理与客户端的SSL/TLS加密和解密，而后端服务器接收未加密的HTTP流量，从而减轻后端服务器的计算压力。",
      "反向代理将SSL加密任务完全交给后端服务器处理。",
      "为了提高性能，完全禁用SSL/TLS加密。",
      "反向代理只对部分请求进行SSL加密。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "SSL卸载（或称为SSL终止）是一个关键的反向代理功能。它指的是反向代理服务器（如Nginx）负责处理与客户端之间的加密通信（HTTPS）。当请求到达代理后，代理会解密请求，然后以普通的HTTP协议将请求转发给内部的后端服务器。这样，后端服务器就不需要消耗CPU资源来处理加解密，从而“卸载”了它们的负担。",
    "source": "文档中「反向代理」部分的「反向代理的核心功能」-「安全性增强」",
    "hint": "“卸载”这个词意味着将某项负担从一个地方转移到另一个地方，从而解放原来的承担者。"
  },
  {
    "question": "在Nginx中配置静态资源服务时，使用 `expires 30d;` 这条指令的主要目的是什么？",
    "options": [
      "设置服务器上静态文件的最长保存时间为30天。",
      "告诉浏览器和CDN等中间缓存，该资源可以被缓存30天，从而减少后续请求。",
      "配置Nginx的访问日志每30天轮转一次。",
      "限制客户端访问该静态资源的频率，30天内只能访问一次。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`expires` 指令用于设置HTTP响应头中的 `Expires` 和 `Cache-Control` 字段。`expires 30d;` 告诉客户端（如浏览器）和中间代理（如CDN），这个资源在未来30天内都是有效的，可以直接从本地缓存加载，而无需再次向服务器发起请求，从而极大地提高了性能和用户体验。",
    "source": "文档中「静态资源服务」部分的「静态资源服务的实现」",
    "hint": "这个指令影响的是客户端或中间代理的行为，而不是服务器本身的文件管理。"
  },
  {
    "question": "根据文档，以下哪项不是Nginx的主要用途之一？",
    "options": [
      "作为负载均衡器",
      "作为数据库管理系统",
      "作为反向代理服务器",
      "作为API网关"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确列出了Nginx的五大主要用途：Web服务器、反向代理服务器、负载均衡器、邮件代理服务器和API网关。Nginx专注于网络流量处理和HTTP服务，它本身不是一个用于存储和管理数据的数据库系统（如MySQL或PostgreSQL）。",
    "source": "文档中「Nginx简介」部分的「3.Nginx的主要用途」",
    "hint": "Nginx的核心工作是处理网络“请求”和“流量”，而不是进行“数据存储与查询”。"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
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          optionsListEl.innerHTML = '';
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            // 重新计算分数
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            nextBtn.style.display = 'block';
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            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
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                // 高亮正确答案
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                    child.classList.add('correct'); // 需要添加CSS样式
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                    child.style.borderColor = '#c3e6cb';
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                // 如果选错了，高亮错误选项
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                    child.classList.add('incorrect'); // 需要添加CSS样式
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            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

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            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  